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automatic Monitoring & Targeting (aM&T) sub-metering systems

1.1           Scope

Automatic Monitoring & Targeting (aM&T) sub-metering systems are products that are specifically designed to measure energy consumption, record, and distribute metered energy data to a platform or system automatically via a variety of communication methods, and analyse and report on energy consumption. aM&T sub-metering systems help users to save energy by identifying energy wastage which they can then take steps to reduce. aM&T sub-metering systems generally consists of three elements: 

  • Sub-metering & sensors
  • Communication and data capture software, and;
  • Monitoring software.

1.2           Definitions

An aM&T sub-metering system captures energy consumption information automatically from which users can gain an understanding of their organisation’s energy use. It consists of equipment components that measure, record, transmit, analyse, report and communicate the energy management information that an organisation needs to manage its energy use (i.e., through implementing an effective energy management system) and highlight any energy wastage.

A wide range of aM&T sub-metering systems are available. The Energy Technology List (ETL) Scheme aims to encourage the installation of sub-metering systems that can facilitate the proactive management of energy use in organisations.

The ETL Scheme covers three categories of product:

  1. aM&T sub-metering software.

  2. aM&T sub-meters and sensors.

  3. aM&T sub-metering systems.

aM&T sub-metering software can be procured through any commercial model as deemed suitable by the consumer. The aM&T sub-meters and sensors will include communication capability. aM&T sub-metering systems are a combination of the above.

To be eligible for inclusion on the ETL, products shall meet the requirements as set out below.

1.3           Requirements

1.3.1       Eligibility requirements 

To be eligible for the appropriate category of product on the ETL scheme, the product shall meet the following eligibility requirements:  

- aM&T sub-metering software 

  • Has some means of automatically capturing, retrieving & storing energy metering data electronically.
  • Enables the analysis of energy metering data with reference to factors that influence energy use by means of visualising energy performance data.
  • Able to present the user/consumer with collected data via graph or data table provided as both `on-line` visualisation or system extraction process to enable results to be used outside the system or transferred to alternative software; the data itself may be configurable for single meter or aggregation of meters where appropriate.
  • Be interoperable by using published communication protocols. 

- aM&T sub-meters and sensors 

  • One or more meters that measure energy use for metering purposes and has communication capability.
  • Be able to meter at least one of the following:

          - Electricity use
          - Gas use
          - Heat use

  • The following sub metering equipment and sensors are eligible but only as a part of a suite of aM&T sub-meters and sensors that directly measure at least one of the three parameters above:

          - Oil fuel flow meters
          - Compressed air flow meters
          - Steam meters

- aM&T sub-metering systems

  • A combination of aM&T sub-metering software and aM&T sub-meters and sensors – not necessarily from the same supplier. In case of combination of aM&T sub-metering software and aM&T sub-meters and sensors from different suppliers, components (hardware and software) shall be interoperable.
  • Be able to meet all the eligibility requirements referenced above, under the product categories aM&T sub-metering software and aM&T sub-meters and sensors.

1.3.2       Functionality Requirements

- aM&T sub-metering software 

aM&T sub-metering software shall be able to: 

  • Automatically capture data from meters or sensors at regular intervals in order to provide energy performance indicators. The collection intervals may be user definable or configured for particular meter types.
  • Store and process meter readings made on a half hourly basis i.e twice an hour (as a minimum). The metering data may be transferred into the data store in real-time or at scheduled times. 
  • Automatically identify and report data collection failures, missing metering data and the failure of communications with meters, transducers, and any other system components. 
  • Present energy consumption data in graphical reporting formats (for example, histograms, line plots, etc.), and in user selectable time intervals / divisions / bases. 
  • Export the collected energy data in a standard format for use in other applications (for example, ASCII files or other formats commonly used by standard office applications).
  • Retain a minimum of 2 complete years of metering data without loss of data resolution or accuracy, in a date/time stamped format, suitable for analysis of trends and patterns.

The aM&T sub-metering software shall provide facilities to enable the user to:

  • Select datasets from individual meters and manipulate them by combining, comparing, and calculating in order to analyse, identify and evaluate instances of energy waste.
  • Undertake regression analysis using two variables in whatever frequency the dataset was obtained, and to display the results in graphical form with a correlation coefficient.
  • Set up automatic exception reporting functions that are capable of basing exception reports on the raw data profile. The frequency capability of notifications should be high with minimum gaps between notifications.
  • Set up standard management reports that enable total energy consumption to be benchmarked against performance standards during a user selectable period. It may also be beneficial to compare energy consumption with the corresponding period in the previous year, including an analysis of energy use by meter, fuel type or energy accounting centre.

- aM&T sub-meters and sensors

Where new meters are being installed, they shall comply with the following requirements: 

Electricity meters shall conform to the following requirements: 

  • Shall have, as a minimum, the capability of displaying the measured active energy and reactive energy. 
  • Be able to measure simultaneous values for voltage and current for each phase. 
  • Be able to measure instantaneous values for voltage, current, active power, reactive power, apparent power, and power factor.
  • Be able to measure cumulative values for active energy, reactive energy, and apparent energy.

Gas meters shall conform to the following requirements: 

  • The volume of the gas should be corrected to standard reference conditions of 15 degrees Celsius and 1.01325 bar(a) 

Oil fuel flow meters shall conform to the following requirements: 

  • Possess a minimum flow rate range of 4:1, where the flow rate range is defined as the range between the minimum flow rate (Qmin) and the maximum flow rate (Qmax).  

For the avoidance of doubt, compressed air flow meters shall conform to the following requirements: 

  • The volume of the compressed air should be corrected to standard reference conditions of 15 degrees Celsius and 1.01325 bar(a)

Steam meters shall conform to the following requirements: 

  • Be capable of displaying the measured steam pressure and temperature, and the current mass flow rate and cumulative mass of steam
  • Shall have, as a minimum, the following components continuously measuring the steam properties and calculating the cumulative steam energy that has passed through the measuring system

  1. A flow meter – which determines how much fluid (steam) has passed through a pipe over a given time period 

  2. A pressure sensor – to measure the pressure of steam flowing through the pipe 

  3. A temperature sensor – to measure the temperature of steam flowing through the pipe 

  4. A calculator/digital integrator – which uses the information provided by the flow meter, temperature, and pressure sensors to calculate the cumulative heat energy transferred through the pipe.  

- aM&T sub-metering systems

aM&T sub-metering systems shall be able to meet all the functionality requirements referenced above, under the product categories aM&T sub-metering software and aM&T sub-meters and sensors. 

1.3.3       Performance requirements

- aM&T sub-metering software

aM&T sub-metering software sold as Software as a Service (SaaS) shall comply with appropriate requirements from ISO 27001 on data security. 

- aM&T sub-meters and sensors

Electricity meters shall meet the accuracy requirements of one of the following: 

  • BS EN 62053-21:2021, Electricity metering equipment. Particular requirements. Static meters for AC active energy (classes 0.5, 1 and 2).
  • BS EN 62053-22:2021 Electricity metering equipment. Particular requirements. Static meters for AC active energy (classes 0,1S, 0,2S and 0,5S).
  • BS EN 50470-1:2006+A1:2018 Electricity metering equipment (a.c.). General requirements, tests and test conditions. Metering equipment (class indexes A, B and C).
  • BS EN 50470-3:2006+A1:2018 Electricity metering equipment (a.c.). Particular requirements. Static meters for active energy (class indexes A, B and C).
  • BS 8431:2010, “Electrical static metering for secondary or sub-metering. Specification” (BSI, ISBN 0 580 451178). Classes 1 or 2.

Gas meters shall meet the accuracy requirements of one of the following standards: 

  • BS EN 12261:2018, Gas Meters - Turbine gas meters.
  • BS EN 12480:2018, Gas Meters - Rotary displacement gas meters.
  • BS EN 1359:2017, Gas Meters - Diaphragm gas meter.

Heat meters shall meet the requirements of: 

  • BS EN 1434-1: 2018, Heat meters. General requirements.
  • BS EN 1434-4: 2018, Heat meters. Pattern approval tests.
  • BS EN 1434-5: 2019, Heat meters. Initial verification tests.

Instrument transformers used to measure energy use for metering purposes shall conform to the Class 1 accuracy requirements of one of the following: 

  • BS EN 61869-2:2012, “Instrument transformers. Additional requirements for current transformers”.
  • BS EN 61869-3:2011, “Instrument transformers. Additional requirements for inductive voltage transformers”.

Oil fuel flow meters shall meet the requirements of:

  • The Measuring Instruments Regulations 2016 (Schedule 1, Section 7).
  • The accuracy classification and Maximum Permissible Error (MPE) as defined within the Measuring Instruments Regulations 2016 (Schedule 1, Section 7).

Compressed air flow meters shall meet the requirements of:

  • The Measuring Instruments Regulations 2016 (Schedule 1, Section 7).

Steam meters shall meet the requirements of:

  • Conformity with the requirements of the appropriate BS EN ISO 5167 series of standards, if relevant for the steam meter

Meters offering equivalent or better levels of accuracy to those specified above will be accepted, provided they meet the accuracy requirements of applicable British Standards. Please note that this includes all electricity, gas and heat meters conforming to the specific accuracy requirements of The Measuring Instruments Regulations 2016.

- aM&T sub-metering systems

aM&T sub-metering systems shall be able to meet the performance requirements referenced above, under the product categories aM&T sub-metering software and aM&T sub-meters and sensors. 

1.4           Measurement and Calculations 

1.4.1       Measurement standards 

See standards reference in section 1.3.3. 

1.5           Verification for ETL Listing

  • For aM&T sub-metering software, the software must be approved under BSC Procedure BSCP601 to read half hourly data from meters and devices.[1] This may be evidenced by listing of the software on Compliance and Protocol Approvals documents.
  • For aM&T sub-meters and sensors, any of the following testing routes may be used to demonstrate the conformity of products against the performance requirements in section 1.3.3: 
  • In-house testing  
  • In-house testing – Self-tested and verified or cross-checked by an independent body
  • Witnessed testing
  • Independent testing 

Further information regarding the first three routes can be found in the ETL Testing Framework.

  • For aM&T sub-metering systems, both the software and the sub-meters and sensors must be verified, as specified above  

Manufacturers and suppliers shall provide technical specifications, sales brochures and/or instruction manuals to evidence the conformity of their products against the eligibility and functionality requirements in sections 1.3.1 and 1.3.2, respectively.

1.6           Conformity testing

Products listed on the ETL may be subject to the scheme’s conformity testing programme in order to ensure listed models continue to meet the ETL requirements. 

1.7           Review

1.7.1       Indicative review date  

This specification is scheduled to be reviewed during the 2024/25 review cycle. 

1.7.2       Illustrative future direction of the requirements   

The next technical review will consider: 

  • Revision of criteria as per latest accuracy standards (if any)
  • Including performance (accuracy) criteria for gas flow meters and compressed air flow meters – in compliance with Combined Heat and Power Quality Assurance (CHPQA) standard
  • Including gas flow meter technologies included such as Coriolis, Vortex, Ultrasonic & Thermal, etc.
  • Including standards against meter safety
  • Including data security standard for package sales of software
  • Updating functionality requirements for electricity meters, such as:

          - Electricity meters to have, as a minimum, the capability to measure voltage dips, swells, interruptions, and harmonics in accordance with BS: EN50160. 

          - Electricity meters to have the capability to measure voltage and current events and have a capability to produce results for tables and timelines of voltage and current events as defined for Class S methodology in BS: EN61000-4-30.

 

[1] BSC Procedure BSCP601 (‘Metering Protocol Approval and Compliance Testing’) specifies the process by which meter manufacturers demonstrate that their Metering Equipment is of an appropriate type and remains fully functional and accurate.